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I've been working on cars since age 11 and was happy to be given a 1999 Deville from a guy at church. He'd given up on it.

Body and interior are in excellent condition. More brand new parts than you can shake a stick at. Down to brass tacks...

It's overheating. The guy that owned it before me got it up to 250F. He pulled over and killed the engine. From that point and without his knowledge, it blew out the freeze plug from the head. I was able to fix that. I've never had a car run 205F-225F and be considered normal. I need to know how to keep this from getting over 190F - even if I have to rig/modify it.

New water pump and belt. I had helped him wire the fans direct with a switch so we could control the on/off, thinking, hopefully that this would force the engine to run at about 165F-185F.

I do realize the whole concept behind a thermostat is so that the engine can get water heat at one point to allow you to have better heat within the car. In some respects, even better running performance. After doing some research on this forum, it looks like I'm going to have to invest in some pipe cleaners.

I have flushed the cooling system and went so far as to take the guts out of the thermostat so I could still use the rubber ring to keep it from leaking.

Noticed some oil loss but there is no water going into the oil nor is there any water coming out of the tailpipe.

I look forward to any comments and advice. Thank you in advance. God bless!

Billy

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There is a hose that runs to the surge tank. On the engine side, its connected to a "bolt with a hole" in it. Remove the bolt, and make sure there is nothing blocking it, and hat this passage is clean and clear. On a cold engine, you can start it, and verify you see flow.

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As Jim said - the Northstar is designed to run between 195 - 210 degrees. Why do you think you need to re-engineer the cooling system?

Do the fans operate normally (without being forced on)? Have you verified you have coolant flow from the purge line to the surge tank?

If there is coolant flowing through the purge line, the next step would be to test the coolant for combustion gasses before going any farther.


Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Check your purge line for flow. If you can take a smell of the radiator cap and surge tank to see if it smells like gas. If you can drive the car hard and do a block test to confirm.

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If the coolant is less that 50-50, the car can use coolant and overheat.


CTS-V_Dashboard.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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It's not uncommon for Northstar engines to use oil. 1 qt, per 1000-1500 miles is considered normal by GM, plus they are also known for leaking oil at the half case seals.

Others have already advised you to check the flow at the hose runnng to the expansion tank. Check this first. No flow here can cause all kinds of overheating issues. If you have flow there and the engine still overheats at highway speeds or when pulling a hill over 55 MPH then you most likely have a head gasket issue. Do a block test. The kit is not that expensive from NAPA or you can use one from Autozone and only pay for the blue dye.

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It's not uncommon for Northstar engines to use oil. 1 qt, per 1000-1500 miles is considered normal by GM, plus they are also known for leaking oil at the half case seals.

Others have already advised you to check the flow at the hose runnng to the expansion tank. Check this first. No flow here can cause all kinds of overheating issues. If you have flow there and the engine still overheats at highway speeds or when pulling a hill over 55 MPH then you most likely have a head gasket issue. Do a block test. The kit is not that expensive from NAPA or you can use one from Autozone and only pay for the blue dye.

Leaks at the case half will usually not be noticed or will not drip to the ground. If the leak drips to the ground, it is most likely the oil manifold plate that is between the oil pan and the lower crankcase half.


Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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4.6 N* overheating after 20 - 30 minutes run time.  A quick background on this issue.  Its in a 99 Devile and have replaced just about everything in the cooling system. And YES that includes replacing the head gaskets ( With repaired head bolt inserts) engine still overheated, there is no water in oil, no oil in the water but noticed restarting after a hot soak ( 15-20 minutes sitting after shutting engine off when hot) a puff of blue/white smoke would come out of exhaust. Decided to take a break from this stupid engine and come back to it later after my head cleared. While working on bullet proofing a powerstroke (replacing the EGR Cooler with an after market upgraded version) it occurred to me to check the water pump housing. Removed the exhaust tube coming in from the cat and the one coming out going to the intake, made a simple plate to cover the 2 holes on crossover just in case it leaked coolant which it didn't or at least hasn't yet, drove and no more over heat. and since this car is in a non-emission state. thats the way its staying.  :blush: Apparently it's cracked and leaking exhaust coming up for the EGR system. I know, makes no since seeing how the coolant has more pressure in its system than the exhaust, you would tend to believe the coolant would be running out the tailpipe. But this does explain the block test coming back positive (exhaust in the coolant). Doesn't really explain the puff of smoke but at this point i'm not going to worry with that. In case your wondering i crimped the EGR tube so its not blowing hot exhaust gas into the engine compartment. Like i said non-emission state. And NO the SES light is not on. :P While this is by no means a typical issue on these engines. Just one i came across.

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WoW:excl:

Good find too BTW.

I would think, that at engine off on a hot soak it should have puddled coolant somewhere in the EGR passage or exhaust.. So if you pull the EGR is the pintle steam cleaned? 

On the 6.0 cooler upgrade that looks like a PITA. Are you installing the engine oil cooler upgrade also? Let me know how that goes for you. I can get a 03 6.0 F350 pretty cheap but it is puffing white smoke too. I didn't want to tackle all that. It looks REAL UGLY...

Edited by OldCadTech

THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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I would run the other way from a 2003 6.0. The oldest I would buy would be a 2008 as they made alot of improvements based on the prone failures of the earlier years.

I have worked on a good hundred of the 6.0s and They are all in Buses. Not much fun.

If I were to replace the egr cooler I would pull the oil cooler and rebuild it. If the tube to the turbo is not a solid pipe, replace it. 

sorry I could go all day. 

As for the exhaust issue with the EGR, where do you think the crack is located? Must have been interesting to figure that out. How far has it been driven since it is no longer overheating?

Thanks for posting


GM FAN FOREVER

Nice, clean, luxury= fine automobile

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4 hours ago, rockfangd said:

If I were to replace the egr cooler I would pull the oil cooler and rebuild it. If the tube to the turbo is not a solid pipe, replace it. 

Hmm, I thought the surface area of the oil cooler was too small. No? - Yes?

How do you rebuild an oil cooler?

Edited by OldCadTech

THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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12 hours ago, OldCadTech said:

Hmm, I thought the surface area of the oil cooler was too small. No? - Yes?

How do you rebuild an oil cooler?

I think that the engine that they are referring to is a Ford 6.0 liter truck V8.  The 1999 Northstar oil cooler is in the right radiator tank.  I'm not sure that the VIN "Y" engines had an external oil cooler at all.  A reasonable upgrade for a Northstar for trailer hauling or use in rough or hilly terrain, ir urban use in a hilly city like San Francisco or Seattle, would be an external tube-and-fin oil cooler.  For low speed heavy use as in urban driving, one with an electric fan on it as opposed to mounting in front of the radiator/evap/intercooler assembly would be preferred.

Went to www.chrfab.com to look for oil coolers and find that the web site is down.


CTS-V_Dashboard.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Yes, we were talking 6.0 diesel Ford. There is an update to the EGR cooler and engine oil cooler to prevent the EGR coolers from plugging and cracking and leaking coolant.

Rock said he would rebuild the oil cooler, I was curious as to how one goes about rebuilding an oil cooler. Sounded intriguing to me.


THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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I will PM you so as to not hijack the thread:hatsoff:


GM FAN FOREVER

Nice, clean, luxury= fine automobile

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14 hours ago, rockfangd said:

I will PM you so as to not hijack the thread:hatsoff:

I won't be offended if you copy me on the new thread.  I know nothing about late model Ford truck engines.  I thought that their engine design process was on a par with GM's, but this BS about EGR/coolant leaks in engines less than 10 years old leaves me to wonder what their endurance testing process is.

Back to the subject, or one of the sub-subjects, the web site http://www.chrfab.com is still down, and defaults to an Earthlink page that says that they hold the registration of that URL for somebody.  A web search on "Cadillac hot rod fabricators" turns up the business at 3313 Live Oak Park Rd. in Fallbrook, CA 92028, phone (760) 451-8794.  Further research shows another business name at the same address with nearly the same phone number, (760) 451-8796, A. W. Johnson & Association (instead of Associates, apparently to avoid duplication of another business name).  The local Chamber of Commerce listing for CHRFAB lists its customers as including "Commercial Vehicles , Japanese , Performance Cars , Domestic , British , German , Diesel , Fleets" which are all licensed street and highway vehicles, but not sand cars and such.

The other company, A W Johnson & Associates, does have a web site, that advertises state-of-the-art welding expertise and training, and his resume in includes NAVSEA representative, a civilian employee of Navy procurement.  It has a different phone number, (760) 310-9138, which is a cell phone also in Fallbrook, CA.  The address is home to Alan Wayne Johnson, age 65+, CHRFAB, and several other people in their 60's.  They have a bio page on Alan Johson that has his photo:

http://www.awjohnson.com/alan-johnson

 


CTS-V_Dashboard.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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